The present invention relates to a safety device for control of working apparatuses (19), e.g., presses, which start and operation modes are dependant of essentially simultaneous activation of two separate operating devices (11), which each are being controlled by an operator by means of each hand.
The two hand operating device is a safety device to protect the operator from reaching into areas, which can be dangerous to him, for instance starting a dangerous machine movement. According to present directions, the operating devices must be placed in specific given positions, where the shortest distance of protection can be calculated according to the formula s=vxc3x97t, where s is the distance of protection, v=the hand speed (normally 1.6 m/s when standing or slower work and 2.5 when seated and higher working tempo) and t=the total stopping time of the machine in ms. The control buttons can either be placed in a common housing or be totally separated.
The buttons of the operating devices are surrounded by protective housings to avoid the undeliberated release of the operating device by the operating person or even deliberately by e.g. usage of one of the fingers on one hand and the elbow and with the other hand feeding a work piece into the machine. The protective housings are arranged so that the push buttons are not affected from above, only by pressing from the side. This leads to ergonomically disadvantageous and tiring body posture, together with a decreased working tempo, since the operator has to look at the operating device in order to pass the protective housings.
The object of the present invention is to provide a two hand device which:
neither undeliberately or deliberately can be released by using just one hand, a hand and an arm/elbow, a hand and a foot or in another way, giving the operator a possibility to walk around the safety directions;
will fulfill highly put ergonomical demands;
lacks protective housings which makes the finding of the buttons more difficult;
ensures a rapid and safe starting, and retaining the work operation without being tiring;
characterized by a simple, reliable and cheap design.
The above mentioned objects have been solved by that the push buttons are situated in different relative to, preferably from each other faced planes, that the housing is designed as a rounded knob, e.g. elliptical or hemi-spherical, with a push button arranged on each side of the length axis of the body, and that the housing between the two push buttons is designed with an elevated part, e.g. designed as a ridge or the like, relatively the push buttons in order to separate the operating fingers.